Air pump



FIG. 1 is a perspective view of an air pump, showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left elevational view thereof;

FIG. 5 is a right elevational view thereof;

FIG. 6 is top plan view thereof;

FIG. 7 is a bottom plan view thereof; and,

FIG. 8 is a perspective view thereof, the element shown in broken lines is for illustrative purpose only and forms no part of the claimed design. 

The ornamental design for an air pump, as shown and described. 